Changes in contractile activation characteristics of rat fast and slow skeletal muscle fibres during regeneration

Damaged skeletal muscle fibres are replaced with new contractile units via muscle regeneration. Regenerating muscle fibres synthesize functionally distinct isoforms of contractile and regulatory proteins but little is known of their functional properties during the regeneration process. An advantage of utilizing single muscle fibre preparations is that assessment of their function is based on the overall characteristics of the contractile apparatus and regulatory system and as such, these preparations are sensitive in revealing not only coarse, but also subtle functional differences between muscle fibres. We examined the Ca²⁺- and Sr²⁺-activated contractile characteristics of permeabilized fibres from rat fast-twitch (extensor digitorum longus) and slow-twitch (soleus) muscles at 7, 14 and 21 days following myotoxic injury, to test the hypothesis that fibres from regenerating fast and slow muscles have different functional characteristics to fibres from uninjured muscles. Regenerating muscle fibres had ∼10% of the maximal force producing capacity (P_o) of control (uninjured) fibres, and an altered sensitivity to Ca²⁺ and Sr²⁺ at 7 days post-injury. Increased force production and a shift in Ca²⁺ sensitivity consistent with fibre maturation were observed during regeneration such that P_o was restored to 36–45% of that in control fibres by 21 days, and sensitivity to Ca²⁺ and Sr²⁺ was similar to that of control (uninjured) fibres. The findings support the hypothesis that regenerating muscle fibres have different contractile activation characteristics compared with mature fibres, and that they adopt properties of mature fast- or slow-twitch muscle fibres in a progressive manner as the regeneration process is completed.

Children's takeaway and fast-food intakes: associations with the neighbourhood food intakes : associations with the neighbourhood food environment

Objective: The present study aimed to examine associations between availability of outlets where takeaway or fast food could be purchased and consumption of takeaway or fast food among children.

Design Cross-sectional: Parents completed a questionnaire regarding the frequency per week their child usually ate takeaway or fast foods. The availability of outlets where these foods could be purchased close to home and en route to school was determined with a Geographic Information System (presence of any outlets and density of outlets within 800 m from home and along the route to school, and distance from home to closest outlet).

Setting: Greater Melbourne and Geelong, Australia.

Subjects: Three hundred and fifty-three children aged 5–6 years and 463 children aged 10–12 years.

Results: Overall, 69·4 % of children consumed takeaway or fast foods once weekly or more often. Only one measure of availability of outlets close to home was associated with consumption; each additional outlet within 800 m was associated with 3 % lower odds of consuming takeaway or fast foods at least once weekly (OR = 0·97, 95 % CI 0·95, 1·00). There were no associations between availability en route to school and the likelihood of consuming takeaway or fast food at least once weekly.

Conclusions:  Access to outlets where takeaway or fast food could be purchased did not predict frequency of consumption of takeaway or fast food in the expected direction. Such relationships appear to be complex and may not be adequately captured by the measures of access included in the current study.

Adaptive fast finite time control of a class of uncertain nonlinear systems

This paper concerns the adaptive fast finite time control of a class of nonlinear uncertain systems of which the upper bounds of the system uncertainties are unknown. By using the fast non-smooth control Lyapunov function and the method of so-called adding a power integrator merging with adaptive technique, a recursive design procedure is provided, which guarantees the fast finite time stability of the closed-loop system. It is proved that the control input is bounded, and a simulation example is given to illustrate the effectiveness of the theoretical results.

Fast food purchasing and access to fast food restaurants : a multilevel analysis of VicLANES

Background : While previous research on fast food access and purchasing has not found evidence of an association, these studies have had methodological problems including aggregation error, lack of specificity between the exposures and outcomes, and lack of adjustment for potential confounding. In this paper we attempt to address these methodological problems using data from the Victorian Lifestyle and Neighbourhood Environments Study (VicLANES) – a cross-sectional multilevel study conducted within metropolitan Melbourne, Australia in 2003.
Methods : The VicLANES data used in this analysis included 2547 participants from 49 census collector districts in metropolitan Melbourne, Australia. The outcome of interest was the total frequency of fast food purchased for consumption at home within the previous month (never, monthly and weekly) from five major fast food chains (Red Rooster, McDonalds, Kentucky Fried Chicken, Hungry Jacks and Pizza Hut). Three measures of fast food access were created: density and variety, defined as the number of fast food restaurants and the number of different fast food chains within 3 kilometres of road network distance respectively, and proximity defined as the road network distance to the closest fast food restaurant. Multilevel multinomial models were used to estimate the associations between fast food restaurant access and purchasing with never purchased as the reference category. Models were adjusted for confounders including determinants of demand (attitudes and tastes that influence food purchasing decisions) as well as individual and area socio-economic characteristics.
Results : Purchasing fast food on a monthly basis was related to the variety of fast food restaurants (odds ratio 1.13; 95% confidence interval 1.02 – 1.25) after adjusting for individual and area characteristics. Density and proximity were not found to be significant predictors of fast food purchasing after adjustment for individual socio-economic predictors.
Conclusion : Although we found an independent association between fast food purchasing and access to a wider variety of fast food restaurant, density and proximity were not significant predictors. The methods used in our study are an advance on previous analyses.

The valuation of fast-food outlets : analysis, methodology, and reliability

Fast-food outlets are a significant subsector of the hospitality and tourism property market in Australia, and have experienced significant growth and global change in the past 20 years. However, little attention has been given in professional and academic literature to the valuation methodology and analysis of these properties. This article proposes a working definition of a fast-food outlet, traces recent changes in the structure of the fast-food industry, investigates the major determinants of value with respect to asset value, and examines to what extent these have changed. In particular, it isolates the role of goodwill in assessing going-concern value.

The valuation of fast food outlets in Australia : methodology, analysis and reliability

Fast food outlets are a significant sub sector of the Hospitality and Tourism Property Market and a specialized form of business. This form of hospitality outlet has experienced significant growth and change in the last 20 years. Their value as an asset is therefore of significant interest to many involved in the tourism and hospitality industry, not least fast food operators or potential operators and their financiers. However, little attention has been given in professional and academic literature to valuation methodology, the analysis of the major components of asset value, and the underlying factors which influence asset value. As such the reliability of the valuation process could justifiably be questioned.
This paper sets out a working definition of a fast food outlet. It investigates the major determinants of value with respect to asset value and examines the accepted methods of valuation of fast food outlets in Australia as well as establishing the methods most commonly used. It clarifies the major components of asset value and examines to what extent these have changed with the changing business environment. In particular it isolates the role of Goodwill in assessing Going Concern Value. Sources of data include a comprehensive literature review and personal interviews with professionals involved in the valuation process. The paper concludes that an efficient valuation process requires that fast food outlets be considered as both a real estate and business investment. The contribution of both tangible and intangible assets to the value of the asset must be identified.

Application of fast and robust equalization in communication technology

This thesis explores the potential of several popular equalization techniques and proposes new approaches to overcome their disadvantages. A H2 optimal initialization has been proposed to overcome the slow convergence problem while keeping the simplicity algorithms. The effectiveness of the methods proposed in this thesis has been verified.

Fast recovery from node compromise in wireless sensor networks

Wireless Sensor Networks (WSNs) are susceptible to a wide range of security attacks in hostile environments due to the limited processing and energy capabilities of sensor nodes. Consequently, the use of WSNs in mission critical applications requires reliable detection and fast recovery from these attacks. While much research has been devoted to detecting security attacks, very little attention has been paid yet to the recovery task. In this paper, we present a novel mechanism that is based on dynamic network reclustering and node reprogramming for recovering from node compromise. In response to node compromise, the proposed recovery approach reclusters the network excluding compromised nodes; thus allowing normal network operation while initiating node recovery procedures. We propose a novel reclustering algorithm that uses 2-hop neighbourhood information for this purpose. For node reprogramming we propose the modified Deluge protocol. The proposed node recovery mechanism is both decentralized and scalable. Moreover, we demonstrate through its implementation on a TelosB-based sensor network testbed that the proposed recovery method performs well in a low-resource WSN.

Room temperature fast-ion conduction in imidazolium halide salts

Fast-ion conduction has been observed in the iodide and bromide salts of 1-methyl-3-ethylimidazolium at ambient temperatures. The melting point of these two compounds is above 350 K and even at 273 K the ionic conductivity in the solid-state is greater than 10⁻³S cm⁻¹. Cation diffusion coefficients have been measured using fringe field gradient and/or pulse field gradient ¹H NMR techniques, which indicated cation diffusion coefficients of the order of 10⁻¹⁰ m² s⁻¹ in the solid-state. Remarkably, these values are up to an order of magnitude higher than the cation diffusion coefficient in the supercooled liquid at 293 K. The activation energy for diffusion in the solid-state is extremely small, as is typical of solid-state fast-ion conductors and indicates a change in transport mechanism from the melt to the crystal. The inability to detect an ¹²⁷I signal together with the modelling of the conductivity using the Nernst–Einstein equation suggests that the solid-state conduction is primarily due to cation diffusion. The solid-state fast-ion conduction is most likely related to vacancy diffusion along the cation layers in the crystal. The temperature dependence of the NMR signal intensity indicates that the number of mobile species is increasing with increasing temperature with an activation energy of approximately 20–30 kJ mol⁻¹.